1. Field of the Invention
This invention relates to the field of endoscopic surgical instruments and, more particularly, to such instruments whose distal portion, bearing surgical implements, may be inserted through natural bodily orifices or surgical incisions and guided to and at the surgical site by endoluminal and ultrasound means.
2. Description of Prior Art
The scope of surgical techniques which may be performed endoscopically has greatly expanded in recent years. This rapid growth is the result of increasingly sophisticated ultrasound-guided and endoluminal instruments.
Such instruments and the surgical techniques which have developed in response to their availability have resulted from a need to provide surgical treatment with a minimum of discomfort and risk to the patient and with decreased recovery time. Many surgical procedures which, only a dozen years ago, would have entailed a large incision, a significant level of anesthesia, and a lengthy, closely monitored, recovery can now be performed on an outpatient basis with only minor analgesia.
Typical of modern endoscopic surgical techniques are those now commonly applied to gall bladder removal and hernia repair. As generally performed today, such abdominal surgical procedures may entail the creation of only two small incisions. One of these admits the surgical instrument and the other allows access of an endoluminal (usually fiber-optic) viewing instrument, to guide the surgeon to the surgical site and to allow him to monitor the procedure visually, in real time.
However, in Vaitekunas et al, U.S. Pat. No. 5,275,166 it is pointed out that the difficulty in this type of procedure, and, indeed, in all types of endoscopic surgery, is that the surgeon can not tactually contact the area to which he is applying the surgical techniques. Thus, while the area can be visually monitored, in real time, by use of the endoscope, tiny and similar-looking--structures can not readily be distinguished, as they might be if the surgeon could apply his trained sense of touch.
Thus, Vaitekunas describes an earlier patent issued to Silverstein et al--U.S. Pat. No. 4,770,185 in which output from a catheter introduced ultrasound transducer is caused to generate a Doppler signal to produce an audible sound, varying with the instantaneous transducer output. Since the transparency of bodily tissues to ultrasound (i.e., sound generally in the 5-50 MHz range) varies characteristically and quite predictably, the quality and quantity of the sound generated by the Silverstein loudspeaker allows the surgeon to distinguish certain internal tissues and processes in real time, namely here, venous versus arterial blood flow.
However, Vaitekunas points out that the Silverstein procedure necessitates removal of the ultrasound transducer catheter and subsequent insertion of the surgical implement catheter, for performance of the surgical procedure, presumably under the continued guidance of a transdermal ultrasound transducer. Accordingly, Vaitekunas seeks to remedy this situation by combining, in one instrument, the ultrasound transducer of Silverstein and the surgical implement, itself.
With this combination, Vaitekunas describes performance of endoscopic abdominal surgery by means of such a combination instrument, inserted into the abdominal cavity through a first small incision, with visual monitoring provided by an ordinary (presumably, fiber-optic) endoscope. Using the audible signals generated from the ultrasound transducer, the surgeon "feels" the tissues seen by means of the endoscope. Thus, he is less likely to confuse the bile duct with a blood vessel.
Although Vaitekunas' combination of an ultrasound transducer and surgical implement in a single surgical instrument is undeniably a great improvement, there is still the problem of the separate endoscope, which someone must manipulate. The surgeon must either manipulate both instruments himself, or he must continuously direct a skilled assistant to manipulate the endoscope, while he controls the surgical implement. This creates an ongoing, unwanted distraction for the surgeon, who would undoubtedly rather concentrate on the surgical procedure.
Approaching the ultimate problem from another direction, for a moment, it may be instructive to examine other developments and their deficiencies. These developments relate primarily to the field of intrauterine endoscopic surgery.
In modern intrauterine surgery, a surgical instrument contained within a catheter is inserted transcervically into the uterus. Typical of such an instrument is a resectoscope. At the distal end of this device are two projecting apparatus: the surgical implement itself, usually a mono-polar electrode by which the resection is performed; and a fiber-optic endoscope, by which the surgeon visually monitors the procedure. Since the distal end of the endoscope is located precisely adjacent to the tip of the electrode, the surgeon may continuously view the electrode and its activity at the surgical site, and is thus able to perform intricate intrauterine surgical procedures. The fact that a modern resectoscope has an external diameter of only a few millimeters, often less than five millimeters, means that such a procedure may be conducted with an absolute minimum of discomfort to the patient, both in insertion and in the course of movement within the uterus. In fact, some intrauterine surgical procedures may now be conducted, using such a resectoscope, with minimal or no analgesia.
There are potential hazards in the use of a resectoscope. While the surgeon is able to visually monitor the procedure in real time with great precision, this is, after all, only a surface view. If, for example, a small blood vessel lies just below the interior uterine surface in close proximity to the surgical site, the surgeon might not be aware of this unless an accident occurs and the vessel is cut by the electrode. Even more serious is the possibility that in a fairly invasive surgical procedure a uterine puncture, or puncture of the underlying bowel might occur. These events are particularly significant and dangerous, because endoscopic surgery, particularly noninvasive surgery of the general type described, may be and will increasingly be performed an outpatient basis. Thus, in such an occurrence remedial procedures and apparatus might not readily be available, and the patient is exposed to the risk of serious complications.
Recognizing this risk, a number of researchers have investigated the use of ultrasound in support of resectoscopic intrauterine surgery. In a paper entitled "Intraoperative ultrasound guidance for intrauterine endoscopic surgery", published at pages 654-656 of Volume 62, Number 3 of Fertility and Sterility (September 1994), the authors, Drs. Gerard S. Letterie and Dawna J. Kramer, describe the positive results of their study of transabdominal ultrasound monitoring of resectoscopic procedures. It should again be pointed out in this context, that we are still referring to remote monitoring of the surgical site, here transabdominally. Still, the surgeon manipulating the resectoscope and visually monitoring the site through the endoscope can only know the approximate location of underlying structures. Not enough precision is provided by this method.
In "Intrauterine Ultrasonography with a High-Frequency Probe: Preliminary Report", Drs. Akihiko Kikuchi, Takashi Okai, Koichi Kobayashi, Masato Sakai, Eiji Ryo and Yuji Taketani report, at pages 457-460 of Instruments & Methods, Volume 85, Number 3 (March 1995) report that, by transcervical insertion of an ultrasound transducer probe of 2 millimeters diameter without analgesia they were able to discover and classify a number of uterine anomalies with some precision.
The latter closely resembles the above teachings of Silverstein et al, in that surgery to remove such anomalies would necessitate removal of the ultrasound transducer catheter and subsequent insertion of, presumably an ordinary, modern resectoscope, probably with transabdominal ultrasound monitoring.
What is needed, then, is a surgical instrument which can be controlled entirely by the surgeon himself, which combines the surgical implement, endoscopic monitoring means and an ultrasound transducer, all directed, or directable at the precise surgical site to allow the surgical procedure to proceed, internally, with both surface (optical) and subsurface (ultrasound) real time monitoring. It would be particularly beneficial to provide such an instrument whose distal housing is sufficiently small in diameter to permit insertion through a single, small surgical incision or preferably, which is incorporated within a catheter, so that insertion might be made through a small natural bodily orifice without the need for an incision.
What is also needed is such an improved apparatus which, by use of precise ultrasound monitoring through use of a transducer in close proximity to the distal end of the surgical implement, entirely obviates the need for any optical monitoring at all, whether by incorporated fiberoptic endoscopic means or otherwise.
Finally, what is needed is a surgical instrument which combines a surgical implement with an ultrasound transducer located at or precisely near the operative focus of the surgical implement with or without the addition of a similarly-placed endoscope, which is miniaturized and contained within a catheter of sufficiently small diameter to permit use of the instrument by insertion through a single, small surgical incision or preferably through small natural bodily orifices, such as the cervix or the urinary canal to facilitate noninvasive surgical procedures (e.g., within the uterus, the bladder, the prostate, the cranial sinuses and the ear) with the need for a significantly lesser degree of analgesia.